Ammonium Hydroxide → (9S)-9-ethyl-3-hydroxy-6-nitro-7,8,9,10-tetrahydropyrido[3,4-f]quinoxalin-9-ium-2-olate

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Reaction Steps

A solution of 9-ethyl-1,4,7,8,9,10-hexahydro-pyrido[3,4-f]quinoxaline-2,3-dione (0.61 g, 2.16 mmol) in 20 mL of concentrated sulfuric acid was treated with a solution of potassium nitrate (0.25 g, 2.47 mmol) in 2 mL concentrated sulfuric acid. After stirring for 3 hours at room temperature, the reaction mixture was poured onto ice and cooled in an isopropyl alcohol/dry ice bath. Ammonium hydroxide was added to adjust the pH to 8.9, and the yellow solid was collected by filtration (0.59 g, 94% yield).

Provenance & Evidence